Natural infection of Ornithogalum mosaic virus on Iris from India.

Iris ( Iris hollandica ) is susceptible to infection by a number of potyviruses including Iris mild mosaic virus , Iris severe mosaic virus and Bean yellow mosaic virus (Van der Vlugt & Derks, 1995). In a survey of iris plantations in and around the Kangra valley (Himachal Pradesh), plants were found exhibiting mottle, mosaic, chlorotic spots on leaves and deformed flowers. Plants with symptoms were tested for the presence of the above potyviruses using antibodies specific to these viruses, and some were found negative. However, the negative samples were positive when tested for infection with the help of antibodies specific to the potyvirus group (Agdia, USA). To discover the identity of the virus involved, plants were tested by RT–PCR using a universal potyvirus primer pair (Van der Vlugt et al., 1999)designed to amplify partial coat-protein gene and 3 ′ -UTR of the viral genome. An amplification product of c.800 bp was obtained and the product was cloned and sequenced (EMBL accession AJ850918). The nucleotide sequence was analysed with the sequences available in the blast database (Altschul et al ., 1997). Pairwise comparisons were performed using the align -2 program utilizing the DOTHELEX algorithm (Tatusova & Maiden, 1999). The sequence was found to exhibit a close relationship (99% nucleotide sequence identity) to an isolate of Ornithogalum mosaic virus (OrMV) from iris that has previously been reported from Australia (EMBL accession AF203528). Further, the sequence showed 87–91% identity with OrMV infecting Ornithogalum spp. This is the first report of OrMV infecting iris from India